Load bearing structure

ABSTRACT

A load bearing assembly comprising a horizontal platform mounted on a sub-structure, said sub-structure comprising a plurality of vertical hollow units, each unit comprising a rectangular sheet of substantially rigid material scored along longitudinal lines into rectangular sections and folded and joined to form a box tube unit.

United States Patent [191 Bartels LOAD BEARING STRUCTURE [76] Inventor:Friedrich Bartels, Via Baraggie 3,

Ascona, Switzerland [22] Filed: Sept. 20, 1971 21 Appl. No.: 181,814

[30] Foreign Application Priority Data [451 Aug. 14, 1973 PrimaryExaminer-James C. Mitchell Attorney-Woodhams, Blanchard & Flynn [57]ABSTRACT Sept. 28, 1970 Germany P 20 47 611.3

A load bearing assembly comprising a horizontal plat- [52] [1.8. CI108/161, 108/51, 108/56 7 form mounted on a Substructure saidSubstructure Int. p i i g a of vertical hollow i each 0 Search 56, unitcomprising a rectangular Sheet of substantially 52/615 rigid materialscored along longitudinal lines into rectangular sections and folded andjoined to form a box [56] References Cited tube unit UNITED STATESPATENTS 3,664,906 5/1972 Hartig 52/615 X 17 Claims, 10 Drawing Figures z7 Z0 Z4 0 l/ J/ I LOAD BEARING STRUCTURE This invention relates to aload bearing structure having a horizontal platform for the load and asubstructure between said platform and the ground or floor.

The main object of the invention is to provide a structure which can beproduced cheaply and quickly, primarily for use in theatres andexhibitions and which are easily transportable. A further object is toprovide a structure which when not in use, can be stored conveniently ina small space and which can be set up for use easily. Another object isto provide a construction in which the sub-structure can take variousforms and built to different heights using standard units.

According to the invention there is provided a load bearing assemblycomprising a horizontal platform mounted on a sub-structure saidsub-structure consisting of a plurality of vertical hollow units, eachunit comprising a rectangular sheet of substantially rigid materialscored along longitudinal lines into rectangular sections and folded andjoined to form a box tube unit.

The units used can be of identical form, or units of different form canbe built up as a super-structure.

The adjacent sides of units can be secured together either temporarilyor permanently, or a means such as a lattice structure, can be used tohold the units together.

In an embodiment, each unit consists ofa rectangular sheet divided byscore lines into three main sections of identical width and extendingtherefrom, three further sections also divided by score lines, two ofwhich are identical and constitute strips for the joining together ofthe blank, the three sections of identical width being folded in thesame direction relatively through 90 and the other three folded throughangles such that the vertical edge of the end section thereof abuts thescore line between the first and second of the three identical sections.

In another embodiment each unit consists of a rectangular sheet dividedby score lines into four main sections of identical width and threefurther sections also divided by score lines, two of which are of thesame width and joined by a wider section, said two serving as fasteningstrips for the joining together of the unit, the first four foldingsections being folded in the same direction to form a square boxstructure and the three further sections folded in a substantiallyZ-shaped manner, the two of the same width being secured to adjacentsurfaces of the box forming sections.

Each unit may also consist of a rectangular sheet having three sectionsdivided by score lines and folded in Z-shaped manner, the end sectionsbeing of identical width and the median section wider than said endsections.

In a further embodiment each unit consists of a rectangular sheet havingfour main sections divided by score lines and of identical width and,three further sections divided by score lines and extending from oneedge of an end main section, the end sections of the further sectionsbeing of identical width, the four main sections being folded in thesame direction to form a square box structure with the one furthersection adjacent the one main section secured thereto, the intermediatesection extending obliquely from the one main section towards itsadjacent main section with the other end section secured to saidadjacent main section.

The load distributing surface of the load bearing structure inaccordance with the invention is preferably a wooden plate or boardwhich is placed, in the simplest case, on to the folding units.

The structure of the invention thus consists of constructional elementsor units which are supplied or stored flat and which are made fromblanks or sheets preferably from corrugated cardboard and which, afterfolding up along the scored or fold lines on the blank and after fixingtogether or insertion, are given their stability and, form the desiredconfiguration of the substructure. The connecting of the individualunits can be by stitching, by staples, by adhesives, by adhesive stripsor the like. The load distributing surface needs to be placed onassembled units. If however, on the contrary, bevelled or stepped planeload bearing structure is used, then the surface board can be fixed. Theprovision of theatre, film exhibition and similar structures isconsiderably simplified, since plane load bearing structures can be usedwhich can be assembled on the site by simple means from industriallyfinished constructional units. The units, i.e., the sheets, can bestandardized for economic reasons. They can be identified by differentcolouring according to their intended use and can be delivered andstored in stacks. After the joining together of the units their outersides or visible surfaces can be painted, pasted on or clad with anydesired material in accordance with the intended effect. After thetermination of use, the units can be discarded. Thus, not only is theerection and structural alteration of the structures simplified, butalso the demolition thereof. More especially storage space iseconomized.

Preferred embodiments according to the invention will now be describedwith reference to the accompanying drawings in which:

FIG. 1 is a top perspective view of a load bearing structure in the formof a three-step platform;

FIG. 2 is a view similar to FIG. 1 of a platform;

FIG. 3 shows a lattice-work for the structure according to FIG. 1,

FIG. 4 is a perspective view of a blank for producing load bearingstructures;

FIG. 5 shows the structure according to FIG. 4 in the folded-upcondition; and

FIGS. 6 to 10 show various structures in the foldedup condition forproducing load bearing structures according to the invention.

FIG. 1 of the drawings shows a load bearing structure 10 having a loaddistributing surface in the form of a board 11 (only part of which isshown) and which rests on a plurality of folding plate structures 12 ofcorrugated cardboard, arranged with their longitudinal axisperpendicular to the load distributing surface. The structures 12 areinside a lattice-work 13 providing a cellular structure which also ismade from corrugated cardboard and which, as shown in FIG. 3 consists ofsheet or strip blanks 31, 32 and 33 which interengage by providing cutsor incisions 34 in from opposite edges of blanks 31 and cuts orincisions 35 in the blanks 32 at positions corresponding to the cuts orincisions 34, the blanks 33 having no cuts or incisions. Thus, aplurality of rectangular cells are provided by the lattice.

Individual folding structures have, as FIGS. 5 to 9 show, a differentconfiguration and folding arrangement. They consist, as shown best inFIG. 4 of a rectangular blank 40 consisting of corrugated cardboard.

In the case of the embodiment shown in FIG. 4, four folding sections 41,42, 43 and 44 of identical width are provided, followed by three furtherfolding sections 45, 46 and 47. If the sections are folded along scorelines 48 applied on the blank, namely the first four folding sections inthe same direction through respectively 90 and the remaining threefolding sections through angles other than 90 in a substantially S orzig-zag manner in the direction of the third section 43, there then isproduced an approximately parallelepiped hollow body, (FIG. The sections45 and 57 can be connected with the sections 41 and 43 for example bystitching staples 4a or by adhesive, so that a rigid structure capableof supporting loading in its longitudinal axial direction is formed.

FIGS. 6 to show similar folding structures 60, 70, 80, 90 and 100 whichare also constructed from a rectangular sheet of material, e.g.,corrugated cardboard and which are of standard dimensions. In the'caseof the folding structure 60, FIG. 6, three folding sections 61, 62 and63 of identical width are provided, to which three further foldingsections 64, 65 and 66 are connected extending from the freelongitudinal edge of the section 63, the sections 64 and 66 being of thesame width and serving as fastening strips for producing the box likesupport. The first three folding sections 61, 62 and 63 are folded onscore lines in the same direction each through 90 with respect to itsadjacent section and the sections 64, 65 and 66 are folded on scorelines so that the section 66 lies contiguously on the inner surface ofthe section 61 at its end adjacent the section 62, with the section 65oblique with respect to its adjacent sections 64, 66.

FIG. 7 shows a folding structure 70, comprising only three foldingsections 71, 72 and 73 folded in a Z or zigzag manner.

In the example shown in FIG. 8 the structure 80 comprises four foldingsections 81, 82, 83 and 84 of the same width and three folding sections85, $6 and 87,

the sections 85, 87 being of less width and being for joiningrespectively to the sections 81, 32. The first five folding sections 81,82, 83, 84 and 85 are folded in the same direction each through 90 withrespect to its adjacent section and the last two sections 86, 87 arefolded through oblique angles towards the second folding surface 82 sothat sections 85, 81 and 87, 82 can be joined.

In the case of the structure 90, shown in FIG. 9, two sections 91 and 92of identical width are provided and subsequent thereto, three sections93, 94 and 95, of which the sections 93 and 95 are of the same widthunited by the shorter section 94. The first two sections 91, 92 foldedthrough 90, the following folding sections through different angles sothat the free edge of the section 95 is received at the score linebetween the sections 91, 92.

The folding structure 100 shown in FIG. 10 has a section 101 to whichthere are linked four folding sections 102, 103, 104 and 105, of whichthe sections 102, 104 are of identical width and are folded insubstantially .U- fashion towards the folding section 101 the section103 forming the base of the U. The folding section 105 is foldedoutwardly and forms a fastening strip.

As already mentioned, the rectangular blanks in stacks with fold lineshave to be folded along these lines and be secured together, as is shownin FIGS. 4 and 5 to form a folding structure, e.g., 40. The individualfolding structures can then be joined together in the number necessaryfor the desired load bearing structure. In the case of load bearingstructure of the form shown in FIG. 1, a system of co-ordinates intendedfor the assembly operation is afforded by the lattice-work formed fromthe strips 31, 32 and 33 which lattice provides a cell-like structure,with the cells filled with folding structures, e.g., 60 and 70. Thefolding structures 60 form the corner and side walls of the load bearingstructure, whilst the folding structures fill the space enclosedthereby. The folding sections, respectively butting against thelattice-work, of the individual folding structures be connected to thelattice-work, for example also by fastening with the aid of staples,cementing, gluing or the like. The load bearing plate 11 completes theplatform. Adjoining this platform, as FIG. 1 shows, are two steps 13 and14 which are formed from folding structures 40. In the case of thisstructure, a lattice-work is unnecessary, the contiguous foldingsections of the folding structures being directly connected to oneanother. Also load distributing plates (not shown) will also be placedon the steps.

FIG. 1 shows, that the structures can be stepped at will in theirheight, according to their purpose.

Shown in FIG. 2 is a platform which is constructed from foldingstructures directly connected to one another without a lattice-work andwhich could also, by way of example, be bevelled or stepped. Theplatform consists of folding structures 40 which form the comers andedges and which are closed on all sides and of which all the internalangles formed by the folding sections are rigidly connected to oneanother, whilst folding structures 70 enclosed by the folding structuresare open on two sides and are rigidly connected, by their parallelfolding sections, tothe adjacent folding sections.

As is evident from the foregoing, plane load bearing structures formedat will can be erected in a simple manner. It is of great advantage forthe different folding structures to be of different colours according totheir purpose, to facilitate correct assembly.

I claim:

1. A load bearing assembly, comprising:

a plurality of sheets of corrugated paper consisting of a plurality ofparallel fold lines therein, said sheet of corrugated paper being foldedalong said plurality of parallel fold lines to define a plurality ofseparate and elongated folded units;

means for securing said folded units in a close sideby-side patternwherein the longitudinal axes of each of said units are parallel, a sidesurface of one of said folded units being spaced from the side surfaceof another adjacent one of said folded units a distance at least equalto the thickness of said corrugated paper; and

a planar load distributing surface means mounted on the'ends of saidelongated units and extending perpendicular to the longitudinal axes ofsaid folded units.

2. A load bearing assembly according to claim 1, wherein said securingmeans comprises two sets of upright, corrugated paper members havingupper and lower edges and assembled with the members of each set inlaterally spaced, parallel relation to each other to define a grid, saidfolded units being received in the spacing between said sets of membersin said grid to maintain the spacing between said folded units.

3. A load bearing assembly according to claim 2, wherein said foldedunits are identical. l

4. A load bearing assembly according to claim 2, wherein said foldedunits are folded from a sheet of rectangularly shaped corrugated paper.

5. A load bearing assembly according to claim 2, wherein said foldedunits are composed of a material blank which consists of at least sevenfolding sections, four of said folding sections are of equal width andare all folded in the same direction each, at 90 to form a hollow unitwhich is quadratic in cross section and open at both ends, a fifth andseventh one of said folding sections being of an equal width and arespaced by a sixth folding section wider than said fifth and seventhfolding sections, said fifth, sixth and seventh folding sections beingfolded into a generally S-shape and positioned inside said folded unit,a first one of said four folding sections being connected to said fifthfolded section and a third one of said four folding sections beingconnected to said seventh folded section.

6. A load bearing assembly according to claim 2, wherein said foldedunits are composed of a material blank which consists of at least sixfolding sections, three of said folding sections are of equal width andare all folded in the same direction each at 90, a fourth and sixth oneof said folding sections being of an equal width and are spaced by afifth folding section which is narrower than said three foldingsections, a fourth folding section is folded at 90 to one of said threefolding sections, said fifth folding section is folded at an obtuseangle with said sixth folding section and said sixth folding section isconnected to said first folding section.

7. A load bearing assembly according to claim 2, wherein said foldedunits are composed of a material blank which consists of at least threefolding sections, a first and third one of said folding sections havethe same width and are spaced by a second one of said folding sectionswhich is wider than said first and third folding sections, said first,second and third folding sections being folded into a Z-shape.

8. A load bearing assembly according to claim 2, wherein said foldedunits are composed of a material blank which consists of at least sevenfolding sections, four of said folding sections are of equal width andare all folded in the same direction each at 90 to form a hollow unitwhich is quadratic in cross section and open at both ends, a fifth andseventh one of said folding sections being of an equal width and arespaced by a sixth folding section wider than said fifth and seventhfolding sections, said fifth, sixth and seventh folding sections beingfolded inwardly of said hollow unit, said sixth folding section defineswith the fifth and seventh folding sections an obtuse angle, said fifthfolding section being connected to one of said four folding sections,said seventh folding section being connected to a second one of saidfour folding sections.

9. A load bearing assembly according to claim 2, wherein said foldedunits are composed of a material blank which consists of at least fivefolding sections, three of said folding sections being of an equal widthand are folded in the same direction each at 90, a fourth and fifthfolding section being narrower than said three folding sections, saidfourth folding section defines a 90 angle with one of said three foldingsections and said fifth folding section defines an obtuse angle withsaid fourth folding section and a free edge of said fifth foldingsection is positioned in a corner formed by the remaining two of saidthree folding sections.

10. A load bearing assembly according to claim 2, wherein said foldedunits are composed of a material blank which consists of at least fivefolding sections, two of said folding sections being of an equal widthand are folded to define a angle therebetween, a third and fifth foldingsection being of a narrower width than an intermediate fourth foldingsection, said fifth folding section being folded to be parallel to oneof said two folding sections and connected thereto.

1]. A load bearing assembly, comprising:

a plurality of sheets of corrugated paper consisting of a plurality ofparallel fold lines therein, said sheet of corrugated paper being foldedalong said plurality of parallel fold lines to define a plurality ofinitially separate and elongated folded units;

means for securing said folded units in a close sideby-side patternwherein the longitudinal axes of each of said units are parallel, theside surfaces of one of said folded units being connected to the sidesurface of another adjacent one of said folded units; and

a planar load distributing surface means mounted on the ends of saidelongated units and extending perpendicular to the longitudinal axes ofsaid folded units.

12. A load bearing assembly according to claim 11, wherein said foldedunits are composed of a material blank which consists of at least sevenfolding sections,

four of said folding sections are of equal width and are all folded inthe same direction each at 90 to form a hollow unit which is quadraticin cross section and open at both ends, a fifth and seventh one of saidfolding sections being of an equal width and are spaced by a sixthfolding section wider than said fifth and seventh folding sections, saidfifth, sixth and seventh folding sections being folded into a generallyS-shape and positioned inside said folded unit, a first one of said fourfolding sections being connected to said fifth folded section and athird one of said four folding sections being connected to said seventhfolded section.

13. A load bearing assembly according to claim 11, wherein said foldedunits are composed of a material blank which consists of at least sixfolding sections, three of said folding sections are of equal width andare all folded in the same direction each at 90, a fourth and sixth oneof said folding sections being of an equal width and are spaced by afifth folding section which is narrower than said three foldingsections, a fourth folding section is folded at 90 to one of said threefolding sections, said fifth folding section is folded at an obtuseangle with said sixth folding section and said sixth folding section isconnected to said first folding section.

14. A load bearing assembly according to claim I], wherein said foldedunits are composed of a material blank which consists of at least threefolding sections,

hollow unit which is quadratic in cross section and open at both ends, afifth and seventh one of said folding sections being of an equal widthand are spaced by a sixth folding section wider than said fifth andseventh folding sections, said fifth, sixth and seventh folding sectionsbeing folded inwardly of said hollow unit, said sixth folding sectiondefines with the fifth and seventh folding sections an obtuse angle,said fifth folding section being connected to one of said four foldingsections, said seventh folding section being connected to a second oneof said four folding sections.

16. A load bearing assembly accoding to claim 11, wherein said foldedunits are composed of a material blank which consists of at least fivefolding sections, three of said folding sections being of an equal widthand are folded in the same direction each at 90, a fourth and fifthfolding section being narrower than said three folding sections, saidfourth folding section defines a angle with one of said three foldingsections and said fifth folding section defines an obtuse angle withsaid fourth folding section and a free edge of said'fifth foldingsection is positioned in a corner formed by the remaining two of saidthree folding sections.

17. A load bearing assembly according to claim 11, wherein said foldedunits are composed of a material blank which consists of at least fivefolding sections, two of said folding sections being of an equal widthand are folded to define a 90 angle therebetween, a third and fifthfolding section being of a narrower width than an intermediate fourthfolding section, said fifth folding section being folded to be parallelto one of said two folding sections and connected thereto.

1. A load bearing assembly, comprising: a plurality of sheets ofcorrugated paper consisting of a plurality of parallel fold linestherein, said sheet of corrugated paper being folded along saidplurality of parallel fold lines to define a plurality of separate andelongated folded units; means for securing said folded units in a closeside-by-side pattern wherein the longitudinal axes of each of said unitsare parallel, a side surface of one of said folded units being spacedfrom the side surface of another adjacent one of said folded units adistance at least equal to the thickness of said corrugated paper; and aplanar load distributing surface means mounted on the ends of saidelongated units and extending perpendicular to the longitudinal axes ofsaid folded units.
 2. A load bearing assembly according to claim 1,wherein said securing means comprises two sets of upright, corrugatedpaper members having upper and lower edges and assembled with themembers of each set in laterally spaced, parallel relation to each otherto define a grid, said folded units being received in the spacingbetween said sets of members in said grid to maintain the spacingbetween said folded units.
 3. A load bearing assembly according to claim2, wherein said folded units are identical.
 4. A load bearing assemblyaccording to claim 2, wherein said folded units are folded from a sheetof rectangularly shaped corrugated paper.
 5. A load bearing assemblyaccording to claim 2, wherein said folded units are composed of amaterial blank which consists of at least seven folding sections, fourof said folding sections are of equal width and are all folded in thesame direction each at 90* to form a hollow unit which is quadratic incross section and open at both ends, a fifth and seventh one of saidfolding sections being of an equal width and are spaced by a sixthfolding section wider than said fifth and seventh folding sections, saidfifth, sixth and seventh folding sections being folded into a generallyS-shape and positioned inside said folded unit, a first one of said fourfolding sections being connected to said fifth folded section and athird one of said four folding sections being connected to said seventhfolded section.
 6. A load bearing assembly according to claim 2, whereinsaid folded units are composed of a material blank which consists of atleast six folding sections, three of said folding sections are of equalwidth and are all folded in the same direction each at 90*, a fourth andsixth one of said folding sections being of an equal width and arespaced by a fifth folding section which is narrower than said threefolding sections, a fourth folding section is folded at 90* to one ofsaid three folding sections, said fifth folding section is folded at anobtuse angle with said sixth folding section and said sixth foldingsection is connected to said first folding section.
 7. A load bearingassembly according to claim 2, wherein said folded units are composed ofa material blank which consists of at least three folding sections, afirst and third one of said folding sections have the same width and arespaced by a second one of said folding sections which is wider than saidfirst and third folding sections, said first, second and third foldingsections being folded into a Z-shape.
 8. A load bearing assemblyaccording to claim 2, wherein said folded units are composed of amaterial blank which consists of at least seven folding sections, fourof said folding sections are of equal width and are all folded in thesame direction each at 90* to form a hollow unit which is quadratic incross section and open at both ends, a fifth and seventh one of saidfolding sections being of an equal width and are spaced by a sixthfolding section wider than said fifth and seventh folding sections, saidfifth, sixth and seventh folding sections being folded inwardly of saidhollow unit, said sixth folding section defines with the fifth andseventh folding sections an obtuse angle, said fifth folding sectionbeing connected to one of said four folding sections, said seventhfolding section being connected to a second one of said four foldingsections.
 9. A load bearing assembly according to claim 2, wherein saidfolded units are composed of a material blank which consists of at leastfive folding sections, three of said folding sections being of an equalwidth and are folded in the same direction each at 90*, a fourth andfifth folding section being narrower than said three folding sections,said fourth folding section defines a 90* angle with one of said threefolding sections and said fifth folding section defines an obtuse anglewith said fourth folding section and a free edge of said fifth foldingsection is positioned in a corner formed by the remaining two of saidthree folding sections.
 10. A load bearing assembly according to claim2, wherein said folded units are composed of a material blank whichconsists of at least five folding sections, two of said folding sectionsbeing of an equal width and are folded to define a 90* angletherebetween, a third and fifth folding section being of a narrowerwidth than an intermediate fourth folding section, said fifth foldingsection being folded to be parallel to one of said two folding sectionsand connected thereto.
 11. A load bearing assembly, comprising: aplurality of sheets of corrugated paper consisting of a plurality ofparallel fold lines therein, said sheet of corrugated paper being foldedalong said plurality of parallel fold lines to define a plurality ofinitially separate and elongated folded units; means for securing saidfolded units in a close side-by-side pattern wherein the longitudinalaxes of each of said units are parallel, the side surfaces of one ofsaid folded units being connected to the side surface of anotheradjacent one of said folded units; and a planar load distributingsurface means mounted on the ends of said elongated units and extendingperpendicular to the longitudinal axes of said folded units.
 12. A loadbearing assembly according to claim 11, wherein said folded units arecomposed of a material blank which consists of at least seven foldingsections, four of said folding sections are of equal width and are allfolded in the same direction each at 90* to form a hollow unit which isquadratic in cross section and open at both ends, a fifth and seventhone of said folding sections being of an equal width and are spaced by asixth folding section wider than said fifth and seventh foLdingsections, said fifth, sixth and seventh folding sections being foldedinto a generally S-shape and positioned inside said folded unit, a firstone of said four folding sections being connected to said fifth foldedsection and a third one of said four folding sections being connected tosaid seventh folded section.
 13. A load bearing assembly according toclaim 11, wherein said folded units are composed of a material blankwhich consists of at least six folding sections, three of said foldingsections are of equal width and are all folded in the same directioneach at 90*, a fourth and sixth one of said folding sections being of anequal width and are spaced by a fifth folding section which is narrowerthan said three folding sections, a fourth folding section is folded at90* to one of said three folding sections, said fifth folding section isfolded at an obtuse angle with said sixth folding section and said sixthfolding section is connected to said first folding section.
 14. A loadbearing assembly according to claim 11, wherein said folded units arecomposed of a material blank which consists of at least three foldingsections, a first and third one of said folding sections have the samewidth and are spaced by a second one of said folding sections which iswider than said first and third folding sections, said first, second andthird folding sections being folded into a Z-shape.
 15. A load bearingassembly according to claim 11, wherein said folded units are composedof a material blank which consists of at least seven folding sections,four of said folding sections are of equal width and are all folded inthe same direction each at 90* to form a hollow unit which is quadraticin cross section and open at both ends, a fifth and seventh one of saidfolding sections being of an equal width and are spaced by a sixthfolding section wider than said fifth and seventh folding sections, saidfifth, sixth and seventh folding sections being folded inwardly of saidhollow unit, said sixth folding section defines with the fifth andseventh folding sections an obtuse angle, said fifth folding sectionbeing connected to one of said four folding sections, said seventhfolding section being connected to a second one of said four foldingsections.
 16. A load bearing assembly accoding to claim 11, wherein saidfolded units are composed of a material blank which consists of at leastfive folding sections, three of said folding sections being of an equalwidth and are folded in the same direction each at 90*, a fourth andfifth folding section being narrower than said three folding sections,said fourth folding section defines a 90* angle with one of said threefolding sections and said fifth folding section defines an obtuse anglewith said fourth folding section and a free edge of said fifth foldingsection is positioned in a corner formed by the remaining two of saidthree folding sections.
 17. A load bearing assembly according to claim11, wherein said folded units are composed of a material blank whichconsists of at least five folding sections, two of said folding sectionsbeing of an equal width and are folded to define a 90* angletherebetween, a third and fifth folding section being of a narrowerwidth than an intermediate fourth folding section, said fifth foldingsection being folded to be parallel to one of said two folding sectionsand connected thereto.